Evonik Degussa Gmbh

Degussa Aktiengesellschaft

Evonik Operations Gmbh

Evonik Industries Ag

Rainer Peter

Klaus Huthmacher

Bernd Drapal

Christoph Weckbecker

Harald Jakob

Stefan Reichert

Hans Joachim Hasselbach

Martin Koerfer

Horst Krull

Steffen Krill

Christoph Kobler

Hans-Joachim Hasselbach

Martin Hateley

Philipp Roth

Martin Körfer

Nongyuan Shi

Christian Kaiser

Barbara Jaeger

Sebastian Bernhardt

Benny Hartono

Frank H&uuml;bner

Christoph Weckenbecker

Barbara Jäger

A process for preparing methionine includes the alkaline hydrolysis of 5-(2-methylmercaptoethyl)-hydantoin (methionine hydantoin) in an aqueous process solution containing alkali metal hydroxide and/or alkali metal carbonate and/or alkali metal hydrogencarbonate. The alkali metal cations in the process solution are potassium and sodium having a K/Na molar ratio range from 99/1 to 20/80.

Process for preparing methionine

This disclosure relates to a process for preparing D,L-methionine by feeding carbon dioxide to an aqueous potassium methioninate solution obtained by hydrolysis of 5-(2-methylmercaptoethyl)hydantoin, in order to precipitate out crude methionine, which is separated off and purified. In this process an aqueous solution of the separated-off crude methionine is purified by recrystallization from a solution containing potassium ions and also a crystallization additive. The crystallization additive is a nonionic or anionic surfactant, or a mixture of different nonionic or anionic surfactants. The recrystallization occurs by introducing a 60 to 110&#xb0; C.-hot methionine solution into a 35 to 80&#xb0; C.-warm methionine suspension, a temperature of which is lower than that of the introduced solution, such that the temperature of the methionine suspension being maintained between 35 and 80&#xb0; C. during the addition. The crystallization additive is a sorbitan fatty acid ester or a mixture of different sorbitan fatty acid esters.

Process for the preparation of methionine

The invention relates to a process for the preparation of D,L-methionine, in which carbon dioxide is fed to an aqueous potassium methioninate solution obtained by hydrolysis of 5-(2-methylmercaptoethyl)hydantoin, in order to precipitate out crude methionine, which is separated off and purified, where, for the purposes of purification, an aqueous solution of the separated-off crude methionine is prepared and subjected to a recrystallization, characterized in that the solution from which the recrystallization takes place contains potassium ions and also a crystallization additive, where the crystallization additive is a nonionic or anionic surfactant, or a mixture of different nonionic or anionic surfactants, and that the recrystallization takes place by introducing a 60 to 110&#xb0; C.-hot methionine solution into a 35 to 80&#xb0; C.-warm methionine suspension, the temperature of which is lower than that of the introduced solution, the temperature of the methionine suspension being maintained between 35 and 80&#xb0; C. during the addition.

Ketomethionine ketals and hemiketals and derivatives thereof are useful as feed additives, in particular for the nutrition of ruminants.

Ketomethionine ketals and derivatives thereof

Process for the preparation of unsaturated 4,5-allene ketones by reaction of tertiary propargyl alcohols with alkenyl alkyl ethers or ketals in the presence of aliphatic sulfonic acids or sulfonic acid salts.

Process for the preparation of unsaturated 4,5-allene ketones, 3,5-diene ketones and the corresponding saturated ketones

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Krombach, Germany

Rainer Peter